The invention relates to a plush or pile knitted fabric which has a basic knitwear containing a plurality of courses and plush yarns or pile fibres which are bound into same, wherein the basic knitwear comprises a plain knitted knitwear formed with at least one first ground or basic yarn and wherein at least one second ground or basic yarn is incorporated into the basic knitwear. The invention also relates to a circular knitting machine for the production of such plush or pile knitted fabrics and comprising a needle cylinder fitted with knitting needles, a sinker ring fitted with sinkers, and at least one knitting system which includes a basic yarn guide for feeding the first basic yarn to all knitting needles, a second basic yarn guide for feeding the second basic yarn and at least one plush yarn guide or a carding device for feeding a plush yarn or the pile fibres.
Plush or pile knitted fabrics have a basic knitwear (i.e. basic knit) and pile fibres or plush loops which are bound thereinto. Since they are used in various ares, in particular in the area of the furniture or motor vehicle industry (upholstery covers) and the textile industry (clothing, decorative materials, technical materials), the requirements which are made in regard thereto vary widely.
For providing a high production speed and the use of reliable knitting machines which are of a simple structure, plush and pile knitted fabrics are preferably provided with a plain (right-left) basic knit. For the production of such basic knits, it is possible to use single-section knitting machines, in particular circular knitting machines, which have only one needle bed (for example a needle cylinder), a sinker bed (for example a sinker ring), and in addition the devices required for feeding plush yarns or pile fibres (see German laid-open applications (DE-OS 31 45 307 and 23 43 886).
Plain basic knits are not suitable for all purposes of use of plush or pile knitted fabrics because of their high level of stretchability, in particular transversely with respect to the wales, and their the lack of anti-ladder capacity. That applies even when, for predominatly visual reasons, each course of the basic knit is composed of sub-courses or course portions, and the basic yarns at successive knitting systems are each fed only to a part of the knitting needles and are set back in regard to the other knitting needles so that each full course is composed of a plurality of sub-courses (see for example German patent specifications Nos. 664 750 and 671 801, EOP 0 051 059 and U.S. Pat. No. 2,710,527). In addition that kind of basic knit is provided in particular when, in dependence on the specific type of knitting machine, it is not possible to associate plush yarns or pile fibres of preselected properties, for example colours, with any desired stitch in a course. The formation of sub-courses then makes it possible for the plush yarns or pile fibres of the same properties to be bound into a respective one of those sub-courses. A consequence thereof is generally lower production speeds and lesser plush yarn or pile fibre densities.
In order to improve the mechanical properties of plush knitted fabrics it is known to provide a double-surface basic knit containing right-right courses (see German published specification (DE-AS) No. 26 37 645). However that is possible only with a complicated machine structure and a low level of density in regard to the plush loops.
It is also known in relation to plush and pile knitted fabrics for a filling yarn (i.e. a backing yarn or a laying-in thread) to be bound in some or all courses of the basic knit (see German laid-open applications (DE-OS) Nos. 18 06 292 and 31 36 670, and EP 0 051 059). Filling yarns of that kind admittedly serve more for the purpose of binding in the plush loops or pile fibres more firmly into the basic knit or consolidating the basic knit, and less for improving, altering or controlling the mechanical properties of a plush or pile knitted fabric. Therefore it has also already been described in this connection (see German laid-open application (DE-OS) No. 2804068) that the stretchability of basic knits may be substantially influenced by the incorporation of filling yarns only when a lower degree of stretchability is imparted to the filling yarns than the stitch-forming basic yarns, in order thereby to limit the transverse stretching of the basic knit to a preselected value. That however is not always desirable for the production of plush or pile knitted fabrics. This is applicable to basic knitting configurations which are produced by the basic yarns formed into stitches only where plush yarns or pile fibres are bound in, while in the other regions the basic yarns are bound in the manner of filling yarns (EP 0 051 059 and 0 072 425). In addition, knitting machines on which such basic knits can be produced would have to be provided with additional patterning arrangements if they are also to be suitable for the production of high-low patterns. Otherwise no needle would be selected for knitting purposes in those zones in which no plush yarns or pile fibres are to be supplied.
In addition, the production of colour patterns in plush or pile knitted fabrics, it is known for floating parts of the basic yarns to be bound into the basic knit by the additional formation of tuck loops or stitches (German laid-open applications (DE-OS) Nos. 24 23 700 and 30 24 705). However floating stitches of that kind only occur when in each knitting system only those needles which are to receive a plush yarn are extended, so that each pattern row is formed by a plurality of sub-rows comprising basic and plush yarns. Therefore the binding off of basic yarn float loops can at any event afford advantages where, due to the system involved, the basic knit has float loops. In contrast, binding procedures of that kind are meaningless in relation to all plush or pile knitted fabrics which, by virtue of the system involved, are produced with a plain right-left basic knit throughout.
Processes are also known which are performed to provide a higher level of plush or pile fibre density, at least in a zone-wise manner, by varying or controlling the basic knit configuration or influencing the properties of the basic knit in particular in those sections in which in accordance with a pattern no plush yarns or pile fibres are to appear, as applies in particular in regard to high-low patterns (German laid-open application (DE-OS) No. 33 05 895). However that results in the production of basic knits which, particularly in the transitional regions between two colour or high-low areas, have an uneven or disturbed effect and do not have any serious advantages over plain right-left basic knits. Apart from that, the production of such fabrics requires knitting machines which, apart from the patterning arrangements intended for needle selection in accordance with the pattern, have patterning arrangements intended for controlling the basic knit configuration.
Also known is a basic knit for plush knitted fabrics, which consists of two basic yarns throughout (German laid-open application (DE-OS) No. 19 43 345 and German utility mode No. 1 964 317). The properties of a plain right-left fabric, due to the principle involved, also cannot be affected thereby. Furthermore that known basic knit does not improve the mechanical properties of the knitware, but for firmly anchor the plush yarns between the two basic yarns as, in contrast to other known processes, the plush yarns are not made into stitches.
Finally it is known (German laid-open application (DE-OS) No. 27 19 578) for reinforcing and/or plush yarns to be additionally bound into a plain basic knit in order thereby to produce selected markings or patterning effects. However such processes have not been used hitherto for providing a plush or pile knitted fabric produced on a production machine, with a unitary basic knit throughout. On the contrary, in the production of socks or stockings and other articles of clothing or parts thereof, they serve for producing particular wearing properties or visual effects, in a zone-wise or section-wise manner. The same consideration also applies in regard to the numerous known plating or backing patterning effects (see for example German published specification (DE-AS) No. 1 056 774) which hitherto have been used exclusively in relation to knitted fabrics without plush yarns or pile fibres.